Epidermal growth factor receptor in human breast cancer: correlation with steroid hormone receptors and axillary lymph node involvement.

Epidermal growth factor (EGF-R) estrogen (ER) and progesterone (PR) receptors were evaluated in 89 primary breast cancers and 23 axillary lymph node metastases. About 57% of primary and 72.2% of metastatic tumors were EGF-R positive and median EGF-R levels were higher in metastatic deposits than in primary breast tumors (P less than 0.05). An inverse distribution of EGF-R and steroid hormone receptor positive tumors was found (chi 2 = 10.87; P less than 0.001 for PR and chi 2 = 5.01; P less than 0.05 for ER) and an interesting correlation between EGF-R expression in primary tumor and axillary lymph node involvement was demonstrated (chi 2 = 21.4; P less than 0.001). Immunohistochemical studies with a monoclonal antibody against EGF-R revealed the presence of EGF-R only in malignant cells. Our data suggest that EGF-R could identify a class of more aggressive breast tumors endowed with a higher metastatic potential and may therefore represent an unfavorable prognostic parameter in breast cancer.